Deasphal ting and dewaxing hydrocarbon mixtures



Patented June 13, 1950 DEASPHALTING AND DEWAXIN G HYDROCARBON MIXTURES Harold C. Myers, Woodbury, N. J., assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application August 27, 1947,

Serial No. 770,953

The present invention relates to the removal of asphaltic materials from hydrocarbon mixtures followed by the removal of high molecular weight parafiinic materials and, more particularly, to the deasphalting and dewaxing of residue. employing a mixture of agents for dewaxing which is also used for deasphalting.

If the general development of the art of deasphalting and. dewaxing petroleum fractions may by summarized in a few words, it may be said that petroleum fractions are deasphalted by using liquefied normally gaseous hydrocarbons such as propane as diluents and dewaxed by chilling, employing as diluent a solvent such as pro-pane or a solvent mixture such as benzene and methylethyl ketone. Although these practices have much in their favor and provide satisfactory results from a technological viewpoint, they possess economic disadvantages. The use of propane as a diluent for dewaxing propane deasphalted oil requires more refrigeration and produces oilier waxes than when employing benzene-ketone mixtures. When the latter mixture is utilized for dewaxing propane deasphalted oil,

distillation is required between the deasphalting and dewaxing operations, necessitating investments in stills and tankage and the expenses incurred in operating this equipment.

It has now been discovered that one diluent can be used for both purposes. The novel diluent is a mixture of propane and an organic carbonate which as a deas-phalting agent is capable of providing a yield of superior quality oil equivalent to that obtained when the same pro quantity of lighter colored, lower carbon residue deasphalted oils than produced by conventional deasphalting which deasphalting mixture is used to dewax the deasphalted hydrocarbon mixtures. It is a further object of the present invention to provide a deasphalting mixture which produces a larger quantity of ,higher viscosity, lighter colored deasphalted oil "of comparable carbon residue than is produced by conventional deasphalting agents which deasphalting mixture is used to dewax the deasphalted hydrocarbon mix- 12 Claims. (01. ice-14.15)

ture. It is also an object of the present invention to provide a deasphalting mixture which retains in the raffinate the fluid constituents of a hydrocarbon mixture which are of high viscosity and which are normally discarded with the asphalt. The present invention also provides for a method of deasphalting and dewaxing hydrocarbon mixtures employing a mixture of agents which can effect economies in the dewaxing operation through vaporization of a portion of the diluent of the diluent-rafiinate phase of the deasphalting operation to chill the raffinate prior to dewaxing. Other objects and advantages are contemplated as will be apparent from the following description.

In general, the use of a mixture of the same substances as a deasphalting mixture and a dewaxing mixture comprises deasphalting a hydrocarbon mixture containing asphaltic materials with a conventional deasphalting agent admixed with a small but efieotive amount of a modifier which is an organic carbonate. The term organic carbonate includes the carbonates of the monovalent residues of aliphatic, cycloaliphatic or aromatic hydrocarbons or heterocyclic compounds such as cyclohexyl carbonate, ethyl carbonate, phenyl carbonate and thienyl carbonate. Preferred among the conventional deasphalting agents are the liquefied normally gaseous hydrocarbons, such as propane and preferred, for practical reasons at present, among the organic carbonates is diethyl carbonate.

The hydrocarbon mixture to be deasphalted and dewaxed is mixed with the deasphalting mixture of deasphalting agent and modifier and the asphaltic material precipitated. The asphaltic material is then washed with fresh deasphalting agent and/or modifier, the washings combined with the raffinate, the rafiinate chilled by vaporization of the excess of the volatile component of the deasphalting mixture or by other means to a temperature at which dewaxing is achieved and the wax Washed with fresh dewaxing mixture.

In the deasphalting operation the asphaltic waxy mixture of hydrocarbons is diluted with from 1 to 15parts by volume of deasphalting mixtwo per volume of hydrocarbon mixture. Preferably, the modifier is used in amounts up to about 20 volume per cent of the deasphalting mixture. Greater amounts of modifier can be used but at the cost of diminishing returns. Preferably the organic carbonate, for example, ethyl carbonate, is used in the rangeof 1 to 12.0 volume percent of the deasphalting mixture. It

is also preferred to use deasphalting mixture to oil ratios of about 3:1 to about :1 by volume. For satisfactory results in the dewaxing operation when using propanediethyl carbonate mixture as a dewaxing mixture, the composition of the deasphalting mixture must be changed from 80 to 99 per cent liquefied normally gaseous hydrocarbon, 20 to 1.0 per cent organic carbonate to a dewaxing composition of about 60-70 volume per cent of organic carbonate and 40-30 volume per cent of liquefied normally gaseous hydrocarbon. The satisfactory range of dewaxing mixture-raflinate ratios is from 8:1 to 02:1 with a ratio of 3 volumes of dewaxing mixture to 1 of raffinate or deasphalted oil preferred. An effective method of achieving this change in the composition of the deasphalting mixture for use as a dewaxing mixture is removal of the propane by evaporation. This not only brings about the required change in the ratio of propane to organic carbonate but also brings about the required chilling of the raffinate to the desired dewaxing temperature. After separation of the dewaxing mixture from the dewaxed, deasphalted rafiinate, the dewaxing mixture is converted to a deasphalting mixture by adding back an amount of propane equivalent to that evaporated from the raifinate after deasphalting or sufficient to provide a deasphalting mixture. When desirable or necessary, the content of organic carbonatedeasphalting agent mixture can be adjusted before dewaxing by the addition of organic carbonate or by depropanizing and adding organic carbonate.

Illustrative of the use of the novel deasphalting-dewaxing mixtures are the following nonlimiting examples.

EXAMPLE I A (deasphalting) A residual oil having a Saybolt Universal Viscosity of 1058 seconds at 210 F. was treated in a tower type deasphalting unit employing 10.5 volumes of deasphalting mixture to one volume of oil. The deasphalting mixture comprised 95.2 volume per cent propane and 4.8 volume per cent diethyl carbonate. In other words, 10 volumes of propane and .5 volume of diethyl carbonate were used for each volume of oil. The tower was operated with a temperature of 180 F. at the top of the tower and a temperature of 120 F. at the bottom of the tower. A yield of 69.2 volume per cent of oil having a Saybolt Universal Viscosity of 165 seconds at 210 F., a color of 375 Lovibond in a A inch cell and a 1.8 weight per cent carbon residue was obtained.

propane. The deasphalted oil (raifinate) -dewaxing mixture (adjusted deasphalting mixture) was chilled to a temperature of 1 F. and the precipitated wax separated. The precipitated wax was washed with about 2 volumes of dewaxing mixture at the temperature of separation. (As is well known to those skilled in the art, the wax can be separated by filtration, centrifugation, etc.) The washed wax amounted to 9.5 volume per cent of the deasphalted raffinate and had a needle penetration of 50. The dewaxed, deasphalted oil after steam stripping had an A. S. T. M. pour point of 10 F., a viscosity of 190 seconds S. U. V. at 210 F., and a viscosity index of 72.

Illustrative of the fact that heavier hydrocarbons than propane can be used is the following in which the deasphalted raffinate obtained according to the description given hereinbefore in IA was dewaxed with a mixture of petroleum ether (pentane-hexane mixture) and diethyl carbonate.

A portion of the deasphalted oil obtained in IA was freed of deasphalting mixture and refluxed with 3 volumes of a dewaxin mixture for each volume of oil. The dewaxing mixture comprised about 65 volume per cent diethyl carbonate and about volume per cent petroleum ether (pentane-hexane mixture). The mixture of deasphalted oil and dewaxing mixture was chilled to 1 F. and the wax separated. The separated wax was washed with about two volumes of dewaxing mixture at the temperature of wax separation. A 10.7 volume per cent yield of wax was obtained. After steam stripping, the dewaxed, deasphalted oil had an A. S. T. M. pour point of 0 F., a viscosity at 210 F. of 193 seconds S. U. V. and a viscosity index of 72.

For purposes of comparison, a portion of the deasphalted oil obtained as described hereinbefore in IA was freed of deasphalting mixture and refluxed with a conventional dewaxing mixture comprising about 54 volume per cent of benzol, about 6 volume per cent of toluol and about volume per cent of methyl-ethyl ketone. Thereafter, the mixture was chilled to 0 F., the wax separated and washed with about two volumes of B-T-M. E. K. dewaxing mixture. A 9.7 volume per cent of wax having a 66 needle penetration was obtained. After steam stripping, the dewaxed, deasphalted oil had an A. S. T. M. pour point of 5 F., a viscosity at 210 F. of 193 seconds S. U. V. and a viscosity index of '70.

For ease of comparison the foregoing results are tabulated as follows:

3 vol.:1 vol. oil vol. 3 vol; 1 vol. oil 65 vol. 3 vol: 1 on 54 Dewaxing Mixture (C2 5 )2C-O 35 (CflHhOhco 35 fit i vol. propane vol. pet. ether E Dewaxing temp, F 1 1 0 Wax volume, per cent yield 9. 5 l0. 7 9. 7

Needle penetratiom 50 66 Steam stripped dewaxed deasphalted oil Pour point, F l0 0 6 Viscosity @2l0 F., seconds 190 193 193 Viscosity index 72 72 (dewm'ng) 70 EXAMPLE II The composition of a portion of the mixture of A raflinate and deasphalting mixture was adjusted to provide a diluent to oil ratio of 3:1 by volume and a diluent composition of about 64 volume per cent of diethyl carbonate and 36 volume per cent A deasphalted, solvent refined residuum having a viscosity at 210 F. of 94.7 seconds (S. U. V.)

was refluxed with about 3 volumes of dewaxing mixture comprising about 65 volume per cent of diethyl carbonate and about 35 volume per cent of intermediate naphtha (predominantly paraffinic) having a boiling range of about 200 F. to about 300 F. The mixture was chilled to F. and the wax separated. The separated wax was washed at the temperature of separation with two volumes of dewaxing mixture. A 12.1 volume per cent yield of wax was obtained. The dewaxed,

A portion of the deasphalted, solvent refined, residual oil used in IIIA and IIIB was refluxed withthree volumes of liquid propane at superatmospheric pressure. The oil-propane mixture was chilled to minus 18 F. and the wax separated. The wax was washed with two volumes of liquid propane at the temperature of separation. A 27.7 volume per cent yield of wax having a 14.9 volume per cent yield of wax having a needle penetration of 60 was obtained. After steam stripping the dewaxed oil had an A. S. T. M. pour point of 30 F., a viscosity at 210 F. of 88.4 seconds (8. U, .V.) and a viscosity index of 97.

f "frtm iinhadi gg fi g i i i gfifig ggij g g i i zi fl at l) needle penetration of 145 was obtained. The 210 F. of 85.9 seconds (s. U. v.) and a viscosity steam F fi l an {iindex of 96. pour point of 20 F., a viscosity at 210 of 88.5

a s B seconds (S. U. V.) and a viscosity index of 96.

A '1 m r1 d 'th is D por on o e same 011 was re uxe W1 three volumes of dewaxing solvent containing 57 A fourth of deasphalted, Solvent Volume per cent benzol 3 Volume per cent toluol refined resldual 011 used in IIIA, 11113 and IIIC and 40 volume per cent imethybethyl ketone The was refluxed with three volumes of conventional oil-solvent mixture was then chilled to 0 F., the 20 dewaxmg solvent compn'smg 54 Volume per cent wax separated and washed at the temperature of benzol, 6 volume per cent 10011191 and 40 Volume separation with two volumes of said solvent. A f cent metr'lyl'ethyl ketoile Z 11.9 volume per cent yield of wax was obtained. olbsolvem mlxture was chlned to minus 1 The dewaxed oil, after steam stripping had an and the wax separated The wax w Washed pour point of F" a viscosity 05 at the temperature of separation with two vol- 210 F. of 92.5 seconds (s. U. v.) and a viscosity was of the Solvent A volume Per cent index of 96. yield of wax having a needle penetration of 60 was obtained. The steam-stripped dewaxed oil EXAMPLE III had an A. S. T. M. pour point of F., a viscosity at 210 F. of 89 seconds (S. U. V.) and a :13 5 Adeasphaltedsolvent refinedresidualstockhav- Vlscoslty Index of 9 inga viscosity at 210 F. of 84.6 seconds (S. U. V.) was refluxed with three volumes of dewax- A portion of the deasphalted, solvent refined ing mixture comprising 66.6 volume per cent diresidual oil used in III A.- C and D was reethyl carbonate and 33.4 volume per cent profiuxed with three volumes of dewaxing mixture pane. The 'oil-dewaxing mixture was chilled to comprising 65 volume per cent diethyl carb0nminus 1 F., the wax separated and the wax ate [(C2H5O)2CO] and 35 volume per cent prowashed at the temperature of separation with two pane. The oil-dewaxing mixture was chilled to volumes of dewaxing mixture. A 13.8 volume per minus 21 F. and the wax separated. The wax cent yield of wax was obtained having a needle was washed at the temperature of separation penetration of 35. After steam stripping, the dewith two volumes of dewaxin mixture. A 19.8 waxed oil had an A. S. T. M. pour point of 15 volume per cent yield of wax having a needle F., a viscosity at 210 F., of 88.6 seconds (S. U. V.) p t o of 6 was obtained. The steam andaviscosity index of 97. stripped dewaxed oil had an A. S. T. M. pour 1, point of 5 F., a viscosity at 210 F. of 88.9 seconds (S. U. V.) and a viscosity index of 93. A portion of the deasphalted, solvent refined, These data are compared in Table II;

TABLE II A B o D E Dewmng Agent 66.6 1. 0110 00 10a 1. 100 1. as 1. on o co at; 336%: as at? olia garg y 25331 oi 5 Vol. dewaxing agent W 3:1 3:1 321 3:1 3:1 Wax separation, -F -l -l -18 l -21 Yield vol., percent 13.8 14.9 27.7 18.6 19.8 Needle penetration of wax- 35 1'45 60 56 Steam stripped dewaxed oil A. S. T. M. pour point, F" 15 30 20 l5 l5 Dewaxing-pour point temperature differential, F 16 31 38 16 26 Viscosity 210 1*. (sec.

s. U. v.) sac 88.4 88.5 89 88.9 Viscosity index V 97 97 96 95 93 residual oil used in IIIA was refluxed at super- Those skilled in the art will recognize the adatmospheric pressure with three volumes of .liqvantages attendant upon the use as a dewaxing uid propane. The oil-propane mixture was mixture of liquefied normally gaseous hydrocarchilled to minus 1 F. and the wax separated. bons, such as propane and organic carbonates. The wax was washed at the temperature of sep- When propane alone is used and a dewaxed oil aration with two volumes of liquid propane. A 7 havingan A. S. T. M. pour point of about 20 F.

is the desideratum, the oil-propane mixture must be chilled to minus 18 P. On the other hand, employing propane and an organic carbonate, such as diet-hyl carbonate, it is only necessary to chill the oil-dewaxing mixture to about minus 1 F.

(IIIC vs. IIID). On the other hand, if the oilpropane-organic carbonate mixture is chilled to minus 21 F. (approximately the temperature of wax separation with propane to provide a dewaxed oil of A. S. T. M. pour point of 20 F.) the dewaxed oil has an A. S. T. M. pour point of F. In other words, the use of organic carbonates in conjunction with liquefied normally gaseous hydrocarbons makes it possible to obtain improved deasphalting and improved dewaxing. Furthermore, to obtain comparable dewaxing results at comparable temperatures it is necessary to use a diiferent dewaxing solvent When propane or the like has been used as a deasphalting diluent. That is to say, in order to obtain a deasphalted, dewaxed, solvent refined oil having an A. S. T. M. pour point of F. when using propane and comparable dewaxing temperatures it is necessary to use benzol-toluol-M. E. K. as the dewaxing solvent; that is to say, one solvent or diluent for deasphalting and another totally different solvent or diluent for dewaxing. On the other hand, employing propane and an organic carbonate as a deasphalting agent it is only necessary to adjust the carbonate concentration and the deasphalting mixture is read for use as a dewaxing mixture.

As used hereinbefore and hereinafter in the claims, the term deasphalting agent includes within its scope those hydrocarbons, mixtures of hydrocarbons, organic'compounds and the like which are known to those skilled in the art to function as diluents or solvents for the non-asphaltic components of petroleum and the term deasphalting mixture includes within its scope the mixture of one or more of said deasphalting agents and one or more of the novel modifiers enumerated hereinbefore conforming to the general formula (R0) 200 where R is the monovalent residue of an aliphatic, cycloaliphatic or aromatic hydrocarbon or a heterocyclic compound.

I claim:

1. A method of deasphalting and dewaxing hydrocarbon mixtures which comprises mixing a hydrocarbon mixture containing asphaltic materials and wax with a deasphalting mixture comprising in excess of 75 volume per cent liquefied normally gaseous hydrocarbons and the balance an organic carbonate, separating asphalt from said mixture, adjusting the composition of the mixture of deasphalted oil and deasphalting mixture to raise the ratio of organic carbonate to liquefied normally gaseous hydrocarbon to about 3:1 to 1:3, and separating wax.

2. A method of deasphalting and dewaxing hydrocarbon mixtures which comprises mixing a hydrocarbon mixture containing asphaltic materials and waxy materials with 1 to 15 volumes of deasphalting mixture comprising liquefied normally gaseous hydrocarbon and about 1.0 to about volume per cent of an organic carbonate, separating asphaltic material and recovering a mixture of deasphalted oil and said deasphalting mixture, adjusting the concentration of liquefied normally gaseous hydrocarbon and organic carbonate in said recovered mixture to provide about 0.2 to about 8 volumes of liquefied normally gaseous hydrocarbon and organic carbonate per volume of deasphalted oil, said liquefied normally gaseous hydrocarbon being present in a concentration of about to '75 volume per cent and the organic carbonate being present in a concentration of about '75 to 25 volume per cent of the mixture exclusive of the deasphalted oil, and separating waxy material.

3. A method of deasphalting and dewaxing petroleum oils which comprises mixing one volume of petroleum oil containing asphaltic and waxy materials with l to 15 volumes of a deasphalting mixture comprising about to about 99 volume per cent liquefied normally gaseous hydrocarbon and about 20 to about 1 volume per cent of organic carbonate to obtain a mixture, separating asphaltic material to leave a mixture of deasphalted oil and deasphalting mixture, adjusting the composition of said deasphalting mixture to provide a mixture of liquefied normally gaseous hydrocarbon and organic carbonate comprising about 25 to about 75 volume per cent of liquefied normally gaseous hydrocarbon and about '75 to about 25 volume per cent organic carbonate to provide a dewaxing mixture, chilling said deasphalted oil in admixture with said dewaxing mixture to a temperature at which wax separates, separating said wax to leave a mixture of deasphalted and dewaxed oil and dewaxing mixture.

4. A method of deasphalting and dewaxing petroleum oils which comprises mixing one volume of petroleum oil containing asphaltic and waxy materials with 1 to 15 volumes of a deasphalting mixture comprising about 80 to about 99 volume per cent liquefied normally gaseous hydrocarbon and about 20 to about 1 volume per cent organic carbonate to obtain a mixture, separating said asphaltic material to leave a mixture of deasphalted oil and deasphalting mixture, adjusting the composition of said deasphalting mixture in situ to provide a dewaxing mixture comprising about 25 to about '75 volume per cent of liquefied normally gaseous hydrocarbon and about 75 to about 25 volume per cent organic carbonate, cooling the mixture of deasphalted oil and dewaxing mixture to precipitate waxy material, separating said waxy material to leave a mixture of deasphalted and dewaxed petroleum oil and dewaxing mixture, separating said dewaxing mixture from deasphalted and dewaxed oil, adjusting the composition of said dewaxing mixture to provide a deasphalting mixture, and deasphalting a mixture of hydrocarbons containing asphaltic material.

5. A method of deasphalting and dewaxing petroleum oils which comprises mixing petroleum oil containing asphaltic material and waxy material with a deasphalting mixture comprising about 80 to 99 volume per cent liquefied normally gaseous hydrocarbon and about 20 to about 1 volume per cent organic carbonate in the ratio of one volume of oil to 1 to 15 volumes of deasphalting mixture, separating a mixture of deasphalted oil and deasphalting mixture from precipitated asphaltic material, adjusting the composition of said mixture of deasphalted oil and deasphalting mixture to provide a mixture of deasphalted oil and adjusted deasphalting mixture, hereafter called dewaxing mixture, containing deasphalted oil and dewaxing mixture in the ratio of about 1 to 0.2 to 1 to 8, said dewaxing mixture comprising about 25 to about 75 volume per cent organic carbonate and about '75 to about 25 volume per cent liquefied normally gaseous hydrocarbon, cooling said mixture of deasphalted oil and dewaxing mixture to a temperature at which waxy material solidifies, separating a mixture of dewaxed, deasphalted oil and dewaxing mixture from waxy material, separating said dewaxing mixture from said deasphalted and dewaxed oil, and adjusting the composition of said dewaxing mixture to provide a deasphalting mixture.

6. The method of deasphalting and dewaxing hydrocarbon mixtures containing asphaltic material and waxy material as described and set forth in claim 1 in which the organic carbonate is diethyl carbonate.

7. The method of deasphalting and dewaxing petroleum oil as described and set forth in claim 3 in which the organic carbonate is diethyl carbonate.

8. The method of deasphalting and dewaxing petroleum oil as described and set forth in claim 5 in which the organic carbonate i diethyl car- Donated 9. The method of deasphalting and dewaxing a residual petroleum oil which comprises mixing a residual petroleum oil and a deasphalting mixture comprising about 92 to about 98.5 volume per c nt propane and about 8 to about 1.5 volume percent of diethyl carbonate in the ratio of 1 volume of residual oil to about 2 to about 10 volumes 0f deasphalting mixture at a temperature at which asphaltic material is substantially im-- miscible with said mixture of esidual oil and deasphalting mixture, separating a mixture of deasphalted residual oil and deasphalting mixture from said immiscible asphaltic material, adjusting the composition of said latter mixture in situ to provide an adjusted mixture containing deasphalted oil and dewaxing mixture in the ratio of 1 to about 0.2 to about 8, said dewaxing mixture comprising about 60 to about 70 volume per cent diethylcarbonate and about 40 to about volume per cent propane, cooling said adjusted mixture to a temperature at which waxy material solidifies, and separating deasphalted and dewaxed oil from waxy material.

10. The method of deasphalting and dewaxing residual petroleum oil as described and set forth in claim 9 in which the composition of the dewaxing mixture is adjusted to provide a deasphalting mixture after separation from the dewaxed, deasphalted oil.

11. The method of deasphalting and dewaxing hydrocarbon mixtures which comprises mixing a hydrocarbon mixture containing asphaltic materials and waxy materials with a deasphalting mixture comprising a deasphalting agent and an organic carbonate, separating asphaltic material from a residual mixture of deasphalted hydrocarbons and deasphalting mixture, adjusting the concentration of deasphalting agent and organic carbonate in said residual mixture to provide a greater concentration of organic carbonate in said residual mixture effective, in conjunction with the reduced concentration of deasphalting agent, as a dewaxing mixture, chilling said residual mixture having adjusted concentration of organic carbonate and deasphalting agent to a temperature at which waxy material present therein solidifies, and separating said waxy material.

12. The method of deasphalting and dewaxing hydrocarbon mixtures which comprises mixing a hydrocarbon mixture containing asphaltic materials and waxy materials with a deasphalting mixture comprising a deasphalting agent and an organic carbonate, separating asphaltic material from a residual mixture of deasphalted hydrocarbons and deasphalting mixture, adjusting the concentration of deasphalting agent and organic carbonate in said residual mixture to provide a greater concentration of organic carbonate in said residual mixture effective, in conjunction with the reduced concentration of deasphalting agent, as a dewaxing mixture, chilling said residual mixture having adjusted concentration of organic carbonate and deasphalting agent to a temperature at which waxy material present therein solidifies, separating said waxy material from a second residual mixture containing deasphalted hydrocarbons and dewaxing mixture, separating dewaxing mixture from said second residual mixture, treating said separated dewaxing mixture to increase the concentration of deasphalting agent to provide a regenerated deasphalting mixture; and deasphalting another quantity of hydrocarbons.

HAROLD C. MYERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,049,046 Bray July 28, 1936 2,137,207 Grahame et a1 Nov. 15, 1938 2,139,000 Cohen Dec. 6, 1938 2,141,361 Pilat et a1 Dec. 27, 1938 FOREIGN PATENTS Number Country Date 413,307 Great Britain July 11, 1934 

1. A METHOD OF DEASPHALTING AND DEWAXING HYDROCARBON MIXTURES WHICH COMPRISES MIXING A HYDROCARBON MIXTURE CONTAINING ASPHALTIC MATERIALS AND WAX WITH A DEASPHALTING MIXTURE COMPRISING IN EXCESS OF 75 VOLUME PER CENT LIQUEFIED NORMALLY GASEOUS HYDROCARBONS AND THE BALANCE AN ORGANIC CARBONATE, SEPARATING ASPHALT FROM SAID MIXTURE, ADJUSTING THE COMPOSITION OF THE MIXTURE OF DEASPHALTED OIL AND DEASPHALTING MIXTURE TO RAISE THE RATIO OF ORGANIC CARBONATE TO LIQUEFIED NORMALLY GASEOUS HYDROCARBON TO ABOUT 3:1 TO 1:3, AND SEPARATING WAX. 